Two-photon microscopy is used to image neuronal activity, but has severe limitations for studying deeper cortical layers. Here, we developed a custom three-photon microscope optimized vertical column of the cerebral cortex > 1 mm in depth awake mice with low (<20 mW) average laser power. Our measurements physiological responses and tissue-damage thresholds define pulse parameters safety limits damage-free imaging. We functional visual neurons expressing GCaMP6s across all layers primary (V1)...

Ultrafast pulsed lasers can be used to achieve remarkable precision during surgical ablation. Through nonlinear interactions with tissue, ultrafast provide a largely non-thermal mechanism of ablation and unique ability create targeted damage within bulk tissue. These advantages have made the ideal tool for various novel applications in ophthalmology. Clinical adoption other remains limited part due lack means fiber delivery laser pulses as flexible, hand-held endoscope. This review provides...

Tensor decomposition has emerged as a powerful framework for feature extraction in multi-modal biomedical data. In this review, we present comprehensive analysis of tensor methods such Tucker, CANDECOMP/PARAFAC, spiked decomposition, etc. and their diverse applications across domains imaging, multi-omics, spatial transcriptomics. To systematically investigate the literature, applied topic modeling-based approach that identifies groups distinct thematic sub-areas biomedicine where been used,...

Towards developing precise microsurgery tools for the clinic, we previously developed image-guided miniaturized devices using low repetition rate amplified ultrafast lasers surgery.To improve speed of tissue removal while reducing device diameter, here present a new 5mm diameter that delivers high-repetition laser pulses high microsurgery.The consists an air-core photonic bandgap fiber (PBF) delivery energy pulses, piezoelectric tube actuator scanning, and two aspheric lenses focusing...

Human cerebral organoids are unique in their development of progenitor-rich zones akin to ventricular from which neuronal progenitors differentiate and migrate radially. Analyses thus far have been performed sectioned tissue or superficial layers due high scattering properties. Here, we demonstrate label-free three-photon imaging whole, uncleared intact (~2 mm depth) assess early events human brain development. Optimizing a custom-made microscope image generated Rett Syndrome patients, show...

In reversal learning tasks, the behavior of humans and animals is often assumed to be uniform within single experimental sessions facilitate data analysis model fitting. However, agents can display substantial variability in sessions, as they execute different blocks trials with transition dynamics. Here, we observed that a deterministic task, mice noisy sub-optimal choice transitions even at expert stages learning. We investigated two sources sub-optimality behavior. First, found exhibit...

The epidermis, the outermost layer of skin, serves as a protective barrier against external factors. Epidermal differentiation, tightly regulated process essential for epidermal homeostasis, formation and skin integrity maintenance, is orchestrated by several players, including signaling molecules, calcium gradient junctional complexes such gap junctions (GJs). GJ proteins, known connexins facilitate cell-to-cell communication between adjacent keratinocytes. Connexins can function either...

We present the optical design of a 9.6-mm diameter fiber-coupled probe for combined femtosecond laser microsurgery and nonlinear imaging. Towards enabling clinical use, we successfully reduced dimensions our earlier 18-mm by half, while improving performance. use analytical computational models to optimize miniaturized lens system off-axis scanning aberrations. The optimization reveals that can be aberration-corrected using simple aspheric relay lenses achieve diffraction-limited imaging...

Normal breast epithelia from BRCA2 mutation carriers display DNA damage and attenuated checkpoint responses.

The water molecule has millions of rotational transitions in the infrared and terahertz region, resulting absorption features dominate transmission spectrum atmospheric measurements, even for propagation distances as short tens centimeters. Remarkably, we observe that at position these resonances increases with THz intensity. We explain this observation by stepwise multiphoton molecules. estimated value effective third-order susceptibility is extremely large: χ(3) = (0.4 + 6i) × 102 m2/V2....

Intrinsic neuronal variability significantly limits information encoding in the primary visual cortex (V1). However, under certain conditions, neurons can respond reliably with highly precise responses to same stimuli from trial trial. This suggests that there exists intrinsic neural circuit mechanisms dynamically modulate intertrial of cortical neurons. Here, we sought elucidate role different inhibitory interneurons (INs) reliable coding mouse V1. To study interactions between...

Abstract Limited throughput is a key challenge in vivo deep tissue imaging using nonlinear optical microscopy. Point scanning multiphoton microscopy, the current gold standard, slow especially compared to widefield modalities used for optically cleared or thin specimens. We recently introduced “De-scattering with Excitation Patterning” “DEEP” as alternative point-scanning geometries. Using patterned excitation, DEEP encodes spatial information inside before scattering. However, de-scatter at...

Abstract Glioblastoma (GBM) is a highly aggressive brain tumor characterized by diffuse infiltration into surrounding tissue, disruption of neural circuitry, and interactions among neurons, astrocytes, blood vessels. This leads to severe functional impairments, including neuronal hyperexcitability, cognitive deficits, in some cases seizures. While substantial progress has been made understanding GBM’s molecular mechanisms, less known about how progression alters connectivity, oscillations,...

Vocal fold scarring is a predominant cause of voice disorders yet lacks reliable treatment method. The injection soft biomaterials to improve mechanical compliance the vocal folds has emerged as promising treatment. Here, we study use precise femtosecond laser microsurgery ablate subsurface voids, with goal eventually creating plane in dense subepithelial scar tissue into which can be injected for their improved localization. Specifically, demonstrate ablation small voids porcine up 120 µm...

The growing interest in performing high-resolution, deep-tissue imaging has galvanized the use of longer excitation wavelengths and three-photon-based techniques nonlinear modalities. This study presents a threefold improvement maximum depth ex vivo porcine vocal folds using third-harmonic generation (THG) microscopy at 1552-nm wavelength compared to two-photon (TPM) 776-nm wavelength. experimental, analytical, Monte Carlo simulation results reveal that THG improves observed TPM...

Nonlinear optical microscopy has enabled in vivo deep tissue imaging on the millimeter scale. A key unmet challenge is its limited throughput especially compared to rapid wide-field modalities that are used ubiquitously thin specimens. Wide-field methods specimens have found successes optically cleared tissues and at shallower depths, but scattering of emission photons thick turbid samples severely degrades image quality camera. To address this challenge, we introduce a novel technique...

Toward developing a new method for restoring tissue viscoelasticity in scarred vocal folds, we previously proposed to localize biomaterials within subepithelial voids ablated using ultrafast laser pulses. The clinical implementation of this necessitates the quantification parameters ablating tissue. Here, present comprehensive study these including ablation threshold and bubble lifetime healthy tissues. We also extracting tissue-specific scattering lengths different layers. This involves...

All-optical polarization switching is demonstrated in a resonant photonic band-gap structure consisting of Bragg-spaced quantum wells (BSQWs). The switch takes advantage the large spin-dependent optical nonlinearities and ultrafast recovery present BSQWs to produce throughputs (greater than 40%), high contrast ratios 40 dB), bandwidths (∼0.6THz), where both time sample are control-pulse-width limited.

We present a comprehensive study of the growth and fabrication Bragg-spaced quantum wells, type resonant photonic band gap structure. To begin, we considered impact disorder drift in periodicity wells on formation gap. found that steady decrease greater than few percent leads to collapse gap, while random well several extra peaks due coupling “intermediate band” states. Next, optimized low x (x⩽0.06) InxGa1−xAs∕GaAs building block structures. Growth parameters include rate, modulation...

We develop an air-core photonic bandgap fiber based piezo-scanning ultrafast microsurgery scalpel with 5mm diameter. Energy transmission, damage thresholds and mechanisms are characterized resulting in 4 ms ablation of 150 × μm tissue area.

Four-wave mixing experiments on GaMnAs indicate an increase in the optical response near band gap with increasing Mn concentration. These findings are attributed to ($s$,$p$)-$d$ hybridization, which leads enhancement density of states valence band. Our show that nonlinearity four-wave technique provides a highly sensitive probe for Mn-related changes electronic structure GaMnAs.

The aim of this study was to differentiate normal and scarred hamster cheek pouch samples by applying a quantitative image analysis technique for determining collagen fiber direction density in second-harmonic generation microscopy images. This paper presents tissue pouches four adult male Golden Syrian hamsters as an animal model vocal fold scarring. One using electrocautery unit the other used control each hamster. A home-built upright microscope compact ultrafast laser were acquire depth...

The group velocity of light is continuously varied in the intermediate band a Bragg-spaced quantum well structure by tuning pulse frequency. Delays 0–0.4bit, without significant distortion, are measured. high index found to lead large Fresnel reflection coupling losses and Fabry-Pérot fringing. Antireflection (AR) coatings deposited on both sides shown improve into but be sensitive small errors (∼1%) AR coating layer thicknesses.

Multiphoton microscopy (MPM) has emerged as a vital tool in neuroscience, enabling deeper imaging with broader field of view, well faster and sub-cellular resolution. Recent innovations ultrafast fiber laser technology have revolutionized MPM applications living brains, offering advantages like cost-effectiveness user-friendliness. In this review, we explore the progress technology, focusing on its integration into for neuroscience research. We also examine utility femtosecond lasers...